The invention relates generally to stock transporting conveyors and more particularly to roller conveyors utilized to receive and rotatingly transport cylindrical stock.
The transportation of objects of longitudinally translating conveyors is perhaps the most commonly utilized scheme for transporting material and partially fabricated products from work station to work station on a production line. Frequently, the conveyor will form a component of the work station in that the product will remain supported on the conveyor during a fabrication step. Furthermore, rotation may be imparted to the product as it translates along the conveyor by driving the conveyor rollers upon which the work rests in order to ensure uniform application of heat, material coatings, or for similar process steps. For example, a given forming operation may require that an article be uniformly heated prior to arriving at a given forming station. Rotating the article while it is translating past various gas or infrared heaters disposed along the conveyor assembly will conveniently achieve this goal. Co-owned U.S. Pat. No. 3,257,186 discloses such a device and function.
A similar approach may be utilized to permit rapid inspection of the entire circumference of a cylindrical container. In U.S. Pat. No. 3,901,381, vertically oriented ware translating on a horizontal conveyor is rotated at an inspection station by opposed, rapidly moving belts.
A forming operation which requires torque or rotational speed in excess of that which can be transferred to the rotating article simply by gravitational contact with the conveyor rollers may necessitate additional componentry. If simply additional torque is required, frictional contact between the rotating articles and the conveyor rollers may be improved by increasing the contact force. A stationary member disposed above the conveyor rollers which engages the upper portions of the articles may be utilized to do so. Naturally, if precautions are not taken, sliding contact between this member and the articles may deface or damage the outside surface thereof. In the second instance, if higher speeds are required, a moving wheel or belt may be utilized to engage the articles from above and rotate them at such a higher desired speed. In most instances, the conveyor rollers will be fabricated of steel or other durable material and damage from scoring or other abrasion will almost invariably result from the sliding of the article against the slower moving conveyor rollers as it rotates.
This specific situation exists in horizontal glass production and tooling lines. Elongate cylindrical glass articles are rotated and simultaneously translated along a roller conveyor past various heating and forming stations. Typically, at least one of these forming stations necessitates the rotation of the articles at a speed greater than that imparted to them by the rotating conveyor rollers. Such higher speed rotation is provided by a rotating wheel or belt disposed above the conveyor assembly at the desired location which serially engages the articles and rotates them at a speed faster than the speed imparted by the conveyor rollers. Generally speaking, the conveyor rollers, due to their exposure to relatively high temperatures, must be fabricated of a hard durable material, preferably metal. The higher speed rotation of the glass articles against the conveyor rollers invariably results in scoring and aesthetic degradation of the exterior surface of the articles.